Usually, before having any cosmetic procedure, the surgeon will require pre-op medical check-up, during which you will be asked questions about your medical history, medication you are taking, ask for further information about your asthma, they will also check your blood pressure and also send you for blood tests to make sure that you are fit and healthy, and able to undergo this procedure. The results then will be reviewed by the surgeon and the anaesthetist, they will then determine if it is safe for you to go ahead with the procedure. However, if you are considering to have these procedures together you need to think about your recovery- you won't be able to sit on your buttock at least 3 days, however it will also be difficult for you to lie on your stomach as you will be after the tummy tuck, so it might be good to consider doing these procedures in two stages.